Protein powder can be a great addition to smoothies, shakes or even meals before or after a workout. But in addition to their benefits, there are some negative aspects to them. Learn more about the side effects of protein powder for gym training to better tailor your diet.
Protein powders can be a convenient way to increase your protein intake on a diet that’s designed to either help you lose weight, gain muscle or simply live a healthier lifestyle. Some of the negative effects associated with protein powders include not getting enough nutrition and consuming too many calories, sugar or protein.
Not Getting Enough Nutrition
Protein shakes can be an excellent substitute for some of those unhealthy protein options you've always eaten, especially if you're trying to develop a healthier diet. Switching out hamburgers, processed meats or high-fat foods for a protein powder shake may be a good start to a new exercise or diet routine.
Protein powders are proteins that have been extracted from their original source, which are either plant-based or animal-based. Some animal-based protein powders include casein or whey protein, which are made from eggs and milk, respectively.
Plant-based protein powders include powders made from soybeans, peas, potatoes or hemp. Depending on what type of powder you buy, the level of protein could be up to 30 grams per scoop, according to Harvard Health.
Powders as a protein supplement could be helpful for gaining muscle mass. A July 2017 study published in the British Journal of Sports Medicine found that protein supplementation resulted in increased gains in both muscle mass and strength in participants who undertook resistance training.
While protein powders may be a great way to get that extra boost of protein you need to refuel your body and build muscle, there may be some cons to them as well. Replacing well-balanced meals with a protein shake for every meal will prevent you from getting the full amount of nutrients your body needs.
According to an April 2019 animal study published in Nature Metabolism, getting all your protein from one particular source, or from a few narrow options, isn't ideal. Ingesting only certain protein powders that contain high levels of branched-chain amino acids (BCAAs) but not others, in particular, showed an association with reduced lifespan. The study also found this narrow protein diet could influence mood and overeating.
Getting Protein From Food
There are nine essential amino acids that are crucial for maintaining everything from muscles and organs to skin and nails. Not all protein sources contain all nine amino acids; this is why it's important to consume a variety of protein in meats, seafood and plants.
If you're looking to supplement your diet with protein powders, be sure to include them in a wider balanced diet. For example, while you may consume a whey protein shake with bananas, almond milk and blueberries before a workout, try to eat protein from whole foods for the rest of the day rather than replacing them with another protein shake.
That could mean making a turkey sandwich for lunch or grilling salmon for dinner. The best proteins that contain all nine essential amino acids include lean meats and seafood, as well as certain plant-based proteins like soy products. Other nutritious protein options, though they contain less protein and not as many amino acids, include legumes, nuts, seeds and whole grains like whole wheat bread.
Difficulty in Losing Weight
This may seem counterintuitive, but consuming too many protein shakes may actually make it harder to lose weight. According to Mayo Clinic, drinking protein shakes in addition to your regular full diet may increase your protein intake, but also cause you to consume too many calories. This may make your weight loss goals more difficult or even cause you to gain weight.
In addition to some protein powders being high in calories, some also contain high levels of sugar. Sometimes this added sugar is meant to provide your shake with a punch of taste, or sometimes supplements contain them to help athletes replenish blood glucose after a workout.
But too many protein shakes high in sugar means you're adding too much sugar to your diet in general. A diet high in sugar has been linked to a myriad of health problems, including an increased risk of heart disease, according to Harvard Health.
Sugar has also been associated with an increased risk of Type 2 diabetes. This is why the side effects of protein powder for gym training may actually be more harmful than good when it comes to weight loss.
Protein shakes may also be less satiating, or filling, than whole proteins and meals. If you're replacing a well-balanced meal with a protein shake instead, you may be consuming the same amount of calories but feel less full, as shakes contain less of the fiber and whole nutrition of regular meals.
Consuming too much protein can also come with side effects. Beyond a short-term high protein diet that is often used by bodybuilders or athletes to gain muscle quickly, an abnormally high protein intake may cause some health issues.
According to a July 2013 study published in ISRN Nutrition, too much protein consumption may create problems for the bones, kidneys and liver. The same study notes there's no reason to go beyond the daily recommended amount of protein, which is 0.8 grams of protein per kilogram of body weight a day.
Whey Protein Side Effects
Whey protein shakes are an excellent pre- or post-workout snack. Whey protein can be helpful in building muscle mass or replenishing your body after rigorous exercise. According to a September 2018 study published in Nutrients, whey protein supplementation improved push-up performance among U.S. Army soldiers, and assisted in lowering fat levels.
However, there are some whey protein side effects that may cause irritation. While there aren't necessarily any serious whey protein dangers, it's important to be aware of how consuming it may contribute to digestive problems. Whey protein may aggravate the stomachs of people who are lactose intolerant or who have a whey allergy.
According to MedlinePlus, whey protein in high doses could potentially cause side effects like thirst, nausea, bloating, cramps, fatigue and headache. MedlinePlus also notes that if you have a milk allergy and are allergic to cow's milk, you should avoid whey protein. If you think you may have an allergy or experience digestive issues when consuming whey protein, it may be best to stick to plant-based protein powders like pea protein powder.
Read more: How Much Protein Is Right For You?
Protein Powders and Chemicals
Under the Dietary Supplement Health and Education Act, the safety or efficacy of dietary supplements like protein powders aren't regulated by the U.S. Food and Drug Administration. This means you often may not be aware of what you're consuming.
According to Harvard Health, some protein powders may contain harmful chemicals. A 2018 report released by the Clean Label Project examined 134 products for 130 toxins and found that protein powder products contained traces of heavy metals, including lead, cadmium and bisphenol A (BPA). They also tested for pesticides and other chemicals linked to health issues.
While some protein powders were shown to have traces of these chemicals, others were free of them. To avoid some of the negative pitfalls of the side effects of protein powder for gym training, be sure to do research on the products before you buy them. Also, make sure to speak with your doctor before starting a heavy protein powder diet, and read the labels to avoid any extra calories, sugar, caffeine or additives.
Most importantly, focus on a well-balanced diet filled with whole foods. Get most of your protein from lean meats, fish or plant-based foods like beans and lentils. With a well-balanced diet, the addition of protein shakes as a pre- or post-workout snack can help boost your fitness goals.
- Harvard Health: The Hidden Dangers of Protein Powders"
- British Journal of Sports Medicine: "A Systematic Review, Meta-Analysis and Meta-Regression of the Effect of Protein Supplementation on Resistance Training-Induced Gains in Muscle Mass and Strength in Healthy Adults"
- Nature Metabolism: "Branched-Chain Amino Acids Impact Health and Lifespan Indirectly via Amino Acid Balance and Appetite Control"
- Mayo Clinic: "I'm Trying to Lose Weight. Could Protein Shakes Help?"
- Harvard Health: "Eating Too Much Added Sugar Increases the Risk of Dying With Heart Disease"
- ISRN Nutrition: "Adverse Effects Associated With Protein Intake Above the Recommended Dietary Allowance for Adults"
- Nutrients: "Effect of Whey Protein Supplementation on Physical Performance and Body Composition in Army Initial Entry Training Soldiers"
- MedlinePlus: "Whey Protein"
- Food & Drug Administration: "FDA 101: Dietary Supplements"
- Clean Label Project: "Clean Label Project Protein Powder Study Results 2018"
- Harvard T.H. Chan School of Public Health: "Protein"